You mentioned a lot of stuff, but I didn't see the typical "tune-up" items. Tune up: Plugs (Motorcraft or Autolite work best), wires, fuel filter, air filter, clean MAF, reset A/F ratio. In your case I would add cleaning and inspecting the IAC, possibly replacing if the IAC plunger doesn't seal. I think cleaning will be fine. I wouldn't suggest replacing it just yet because your idle symptoms can be explained by other issues.

Quote:

Originally Posted by katchoo22

The new cap is like gas caps, clicks when it's tightened, can't overtighten.

Engine coolant systems must be sealed to 6-7 psi or so. That's what keeps the coolant from boiling. These engines run well over the boiling point of water, and probably right up to the boiling point of coolant. 116C is when the low speed fans turn on, 118 is high speed.

Quote:

Originally Posted by katchoo22

The next problem is I have a very rough idle, computer constantly trying to adjust timing.

Yeah, probably a vacuum leak somewhere. The PCV is our usual suspect, but there can be others. As old as the car is, I would inspect each and every line. Trace them down, remove from vehicle, plug one end, and blow into the other end. Rubber parts- bend to expose cracking and dry rotting. Replace as needed. There are not many vacuum lines in this vehicle- it won't take that long.

Quote:

Originally Posted by katchoo22

The car shakes real bad but the motor looks steady under the hood.

You got that one- right? Motor mounts can be tricky. You will be wise to quickly replace the other 2, and to follow the correct procedure for lining the mounts up. Also be sure to jack the engine enough to float the mounts while you tighten the bolts that hold the mount to the engine. You shouldn't be lifting the engine with the mount bolt.

Quote:

Originally Posted by katchoo22

There's also a slight whine coming from the timing belt end (possibly drivebelt or pulleys). Car still has original drivebelt, timing belt, pullies, etc.

That timing belt is probably most of your idling problem. When the belt gets old, it stretches slightly, and this changes the valve timing and the ignition timing. It can also move around while it's running. You should look in your manual about how to inspect a timing belt. I will also suggest purchasing a water pump to go along with this repair. There are some great prices on timing belts at RockAuto.com. Most of that job is work. You can do it- we can help! It's really not all that difficult.

Quote:

Originally Posted by katchoo22

Idler pulley on drivebelt looks scarred but it's not scratched that I can tell. Belt doesn't look bad.

Yeah, your manual won't tell you that in the early 00's, parts makers went from old neoprene belts to newer EPDM belts. EPDM wears differently. Check it out at Gates Rubber website online. Instead of the back wearing off, the ribs wear off.

Quote:

Originally Posted by katchoo22

I can see a very slight draw on the electrical system as the idle pulses.

Or it's just not putting out enough sometimes. Your alternator is suspect at this mileage. Also check the connections of all the wires that go to the battery. Be sure to disconnect the negative terminal before you go checking the positives. As far as alternators go, I always recommend a local rebuilder. Support your local economy, get a better job done, and save money. Those who replaced multiple lifetime warranty alternators in a year agree- go local for electrical rebuilds. The reasons are well documented on this site, so I'm not getting into it. It has to do with business models.

Quote:

Originally Posted by katchoo22

RPMs are hanging up with each shift and when coming to a stop and at idle it hangs the longest, taking a few seconds to level out, as you would expect with a vacuum leak.

Yeah, you'll have that until you get everything sorted out. Just ignore it for now. It might be a sign of a bad IAC, but until you have crossed everything out and still have idle problems- I wouldn't worry about it. The main test for the IAC- does idle remain steady or go up when the AC is on- seems to be failed from your description, but it might be the timing belt, plugs, wires, coil- who knows. Let's test and worry about other stuff before getting back to the idle. Otherwise, you're wasting your time. Concentrate on what you can prove is bad, and let the rest of it wait. Let me add that prove means diagnose- not following crackpot internet advice. Never throw parts at a vehicle to fix it- unless you're rich, then pay someone else- right?

Quote:

Originally Posted by katchoo22

As I'm very new at mechanics (self-taught this last year - but I carry my Chilton's with me everywhere I go, can recite it practically verbatim lol - and have utilized this forum numerous numerous times to guide me along the way) I don't have the skills yet to diagnose more difficult complications and am hoping that someone will recognize what's going on and share their wisdom.

Hogwash. I will make no comment on the wisdom on this board......You're just not asking the right questions to the right people. All this stuff can be tested. You'll get good at working on cars with this one. It seems as if it is going to have problem after problem due to its age and neglect. Start with the more serious problems- timing belt, accessory belt, alternator, and then down the line. First off, go ahead and get those other 2 motor mounts changed. Start a new thread asking advice about how to do those last 2. Otherwise you'll end up killing the passenger mount, and then you'll be back to where you were.

Next we'll work on how to diagnose your timing belt. I would actually think that should be done at this mileage. Typically around 120k is when it goes, and people usually get it repaired, and then sell a car.

BTW, you drastically need a very cheap and easy part- the fuel filter. That's part of routine maintenance. It's probably not all of your problem, but it's part of it. Ask about that, or follow our How-To.

I gotta go to work

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